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Dell 3100cn Repair

One day I tried to fill my dell 3100cn color laser printer, but the "Load Tray Letter" error wouldn't go away. I checked all of the settings, made sure the blue bars in he tray were properly clicked in, tried clearing the nvram, but I couldn't even get it to print the diagnostic pages (turn off the printer, power up holding up and down arrows to get into diagnostic mode). I could print using the MPF tray, so I decided to use that for a few months until I finally got fed up with the error, and decided to figure out what was causing it. As it turns out, it was a mechanical failure, and a very simple fix.

If you look closely at a working 3100cn you might notice that inside the tray there is a metal plate on some springs that pushes the paper up into the feeder mechanism. When you pull the tray out there are some catches that compress the springs to allow you to pull the tray out, and when you push the tray into the printer there are some small plastic clips snapped into the bottom of the printer which release the catches. On my printer one of the clips was completely broken and floating loose in the printer, and one looked like it was about to snap, so I used some 5 minute epoxy to put them back into their corresponding positions--and viola the error cleared. Not bad for a printer that I paid less than $500 for and has over 13000 pages on it

Repair

It is easy to see if your printer needs this repair made, simply pull the tray out completely, and look inside where the tray came from. Near the back of the metal plate that is the bottom of the printer, there should be 2 white plastic clips (you might need a flashlight to be able to see them). If either of them is missing or damaged, then this fix should apply.

A picture of the base plate, and a detail of the clip.

If you do find that one of your clips is damaged, here is the fix:

Release the catches that hold the tray to the printer. Pull the tray out completely, and turn the 2 sliver knobs inside.
Lift the printer off the tray, and set it somewhere safe
Remove the 6 screws holding the plastic covers on the tray mechanism (the part that the tray goes into)
Flip the tray mechanism over so that you are looking at the bottom, and remove the screws holding the base plate on
Remove the base plate, which should look like the picture above
Use some glue (I used 5 minute epoxy, superglue or hot glue would work in a pinch) to attach the clip, making sure to put it into the hole marked 250 (unless you have a 500 sheet tray)

The repaired clip, and a view from the bottom of the tray mechanism.

Update:

I received an e-mail from Kevin:
On the front of the printer, when you pull out bottom tray, you'll see three small, white buttons. Their mounting is poor and if they come loose, you'll get the same symptom. The fix is simple, snap the fixture back in place (to the right, toward the tray).